JPH06142819A - Device for chain link butt welding - Google Patents

Abstract

PURPOSE: To provide a chain link butt welding device which is simple in construction, is capable of simultaneously executing stages of finish bending and butt welding of a chain link and is capable of producing a chain having butt weld zones of high quality. CONSTITUTION: Dies 4 for press welding of the one chain link 1 which is previously bent to a C shape and to be butt welded are simultaneously connected to a voltage transformer 5 for welding by a flexible cable 6 and are used as welding electrodes. A die holder 8 for imparting the press welding force for bending the chain link 1 into a series of the terminal links of the chain to the dies 4 and oscillation joints 7 having oscillation central points 14 on the inner side of the chain link are previously disposed. As a result, the occurrence of the relative movement between the dies 4 and the chain link 1 is averted during the finish bending and butt welding work.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butt-welding device for a chain link, which is made of steel bars which have been bent into a C-shape and are hooked to each other.

[0002]

BACKGROUND OF THE INVENTION AND PRIOR ART German Patent Publication 1
In known devices, such as those described in DE 627715 and German Patent 2,347,768, pre-bent and interlaced chain links are sequentially butt electrowelded one after another. But,
At the end of each welding, the chain link to be welded next at least in each case alternates around its longitudinal axis in one direction or in the opposite direction.

The two steps of bending the chain links and butt welding the ends of the chain links which are pre-bent and hooked together are described in German Patent Publication 162.
As disclosed in Japanese Patent No. 7715, even if the welding stand is provided immediately after the chain holding device and the rotating device in the chain bending machine, basically, they are performed in independent steps. is there. In the case of this known welding machine, both ends of the chain are pressed against each other by means of clamping devices, while both electrodes serve to supply the welding current.

In the case of this known device, as well as in the device disclosed in DE 2347768, the production speed of the chain is basically dependent on the working speed of the welding stand; It is constrained by the indispensable work of rotating chain links.

Furthermore, the butt welding of chain links always requires one special device, which increases the capital investment and thus the manufacturing cost.

[0006]

SUMMARY OF THE INVENTION The present invention provides a high quality butt-welded chain which has a simple structure and operates at the working speed of a bending machine for the chain, and at that time is excellent in quality. An apparatus for butt-welding chain links is provided which allows it to be manufactured.

The present invention has been made by noting that one particularly troublesome problem that arises when simultaneously bending and welding one chain link is to transmit a welding current to the chain link. is there. That is,
If there were relative movements of the contact surfaces between the chain links and the electrodes, this would result in a very high electrical resistance, which would lead to local overheating and burnout of the electrodes and chain links. This is because, at the same time as the result occurs, the execution of butt welding with excellent quality is hindered.

[0008]

Starting from an examination of the above-mentioned drawbacks, the essential point of the means for solving the above-mentioned problems is that in the case of a device of the type mentioned at the outset, one Pre-bent chain on welding machine
To further bend and finish the link, the two dies forming the electrode are connected to each other, and they are connected to each other by a swing joint into the end link of the chain, which is the above-mentioned pre-bent chain. It is connected to two mold holders that can move like bending the link.

When the chain link is bent, this swing joint causes a high conductive resistance between the two dies connected as welding electrodes and the pre-bent chain link. It ensures that no relative movement can take place, so that the total welding current is transferred from the mold to the pre-bent chain link and is required at both ends of the pre-bent chain link. Only heating is done within the shortest time.

In order to minimize the movement of the pre-bent chain link during bending, heating, and pressure contact, the swing center point of the swing joint is pre-bent inside the chain link. It is good to come to. A chain whose swing center point is pre-bent.
Such an oscillating joint placed inside the link is such that the facing surfaces of the mold holder and the mold are located inside the chain link where their common center point is pre-bent. It can be easily achieved by forming an arc.

In order to reduce the friction between the mold holder and the mold, a roller may be arranged between them.

A firm fit of the steel bars to both dies is achieved by using an inner die for molding, which can be split into a pre-bent chain link and spread like scissors. To be done.

The final finished chain link is held in the orthogonal position required for finish bending and butt welding by a holder clamp or positioning clamp, which allows bending, heating, and Each butt welding process can be performed easily.

The arcuate portion of the chain link has the largest mechanical stress in the chain link, whereas the least mechanical stress is in the straight leg of the chain link. Both molds hold the chain link, which is pre-bent, by the arc part of the chain link, and move the straight legs of the chain link facing each other during bending, heating and pressure welding work. It is designed to allow the weld to come to the straight leg of the chain link.

In order to reduce burrs as much as possible during welding, it is advisable to sharpen both ends of the steel bar piece, whereby the material forming the burrs wraps around the peripheral notch and is stamped later to make it easy. There is only a slight burr that can be made very smooth.

[0016]

The present invention will be described in more detail below with reference to the embodiments conceptually shown in the drawings.

FIG. 1 is a view of the device according to the invention with one pre-bent chain link set prior to the bending, heating, and crimping operations, and FIG. 2 is for welding. FIG. 6 is a diagram of a device including one completed chain link.

First, in order to be able to set the pre-bent chain link 1 in this device, a straight steel bar piece is bent into a so-called U-shape. Then, the both ends that are bent and projecting high are bent outward to form a C shape, and then compressed to the state shown in FIG. After the chain link (end link) 2 that has been welded at the end is set between the chain links 1 pre-bent in this way, both free ends of the C-shaped steel bar piece have two molds. 4 is brought to the welding position.

FIG. 2 shows the chain link 2 between the two dies 4 and welded at the butt weld 3 after the welding is completed.

Both molds 4 serve as welding electrodes, so that by means of the two flexible cables 6,
In detail, it is connected to a welding transformer 5 which is a part of a welding machine (not shown).

Both molds 4 are connected to both mold holders 8 via two rocking joints 7. These two rocking joints 7 are composed of a plurality of rollers arranged between the arc-shaped outer surface of the mold 4 and the corresponding arc-shaped surface of the mold holder 8. In order to bend the pre-bent chain link 1 further, both mold holders 8 have their mold systems 8 until their free ends come into contact with each other and the welding takes place in the usual way. And via the work cycle cam 10 by means of the drive 11 to bring them closer together. In order to securely set the pre-bent chain link 1 between both molds 4, the pre-bent chain link 1
An inner mold 12 is interrupted which can be spread like a scissor inside the mold and at the same time also serves as a molding.

The last welded chain link 2 can also be the first link in a chain, but
One holder clamp or positioning clamp 13 is necessary for the welding operation so that it does not come into contact with the pre-bent chain link 1,
It is held at an intermediate orthogonal position between both molds 4. This holder clamp or positioning clamp 13
Can be gripped each time the chain link 2 has just been welded and can be swiveled 180 ° so that it can be rotated 90 °.

Since no relative movement occurs between the two dies 4 and the pre-bent chain link 1 during bending, the pre-bent chain link 1 is Since it is bent around one swing center point 14 which is also the swing center point with respect to 4, the die 4 and the pre-bent chain link 1 have a smaller inductive resistance and a more reliable contact. The result is that satisfactory butt welding with high strength is achieved in a very short time.

[Brief description of drawings]

FIG. 1 is a schematic representation of the device according to the invention with one of the pre-bent chain links set prior to the bending, heating and crimping operations.

FIG. 2 is a schematic diagram of an apparatus including one chain link that has been welded.

[Explanation of symbols]

1 ... Pre-bent chain link 2 ... Chain link (end link) that has been welded at the end 3 ... Butt weld 4 ... Mold 5 ... Welding transformer 6 ... Flexible cable 7 ... Oscillating joint 8 ... Mold holder 9 ... Insert system 10 ... Work cycle cam 11 ... Drive device 12 ... Inner mold 13 ... Holder clamp or positioning
Clamp 14 ... Swing center point

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Karl Christoph Exner Federal Republic of Germany 5000 Cologne 90 Am Markt 6 (72) Inventor Josef Baumsterk Federal Republic of Germany 5300 Bonn 1 West Prussia Strasse 15 (72) Inventor Hall St. Baker Germany 5000 Cologne 51 Tourstock Grütel 104

Claims (8)

[Claims] 1. A device for butt-welding chain links (1) made of steel bars that have been bent in a C shape in advance and hooked to each other, the transformer (5) for welding. Two dies (4) connected to each other to form a welding electrode, -these dies (4) and the pre-bent chain link (1) in the end links of a chain of chains A chain characterized by including a rocking joint (7) connecting between a mold holder (8) that moves to bend into
Equipment for link butt welding. 2. The rocking joint (7) according to claim 1, characterized in that it has its rocking center point (14) inside said pre-bent chain link (1). Equipment for chain and link butt welding. 3. A common rocking center in which the mutually facing surfaces of the mold holder (8) and the mold (4) are inside the pre-bent chain link (1). A chain according to claim 2, characterized in that it is constructed in an arc with points (14).
Equipment for link butt welding. 4. A swing joint (7) including a plurality of rollers is provided between the mold holder (8) and the corresponding mold (4). The chain link butt welding apparatus according to Item 3. 5. An inner mold (12) for molding which can be split into the pre-bent chain link (1) and spread like scissors. The chain link butt welding device described in any one of 1 to 4. 6. The method according to claim 1, characterized in that it comprises a holder clamp or a positioning clamp (13) for holding the finally finished said end link (2) in an orthogonal position. The chain link butt welding device described in any one. 7. The mold (4) grips the pre-bent chain link (1) at the arc portion of the chain link, and then the chain link during bending, heating and crimping operations. 7. The chain-link butt-welding device according to claim 1, wherein the straight legs of both of them are moved by butting against each other. 8. The chain link butt welding device according to claim 1, wherein both ends of the steel bar piece are sharpened.